Nucleophilic Substitution Mechanisms: Stereochemistry, Kinetics, and Structural Influences

Explore the intricacies of nucleophilic substitution reactions in this 52-minute lecture from Yale University's Freshman Organic Chemistry II course. Delve into the process of establishing reaction mechanisms by disproving alternatives, focusing on SN2 substitution as a prime example. Examine five general pathways, including two-step processes involving pentavalent or trivalent carbon intermediates and one-step reactions. Learn to differentiate between these pathways using experimental tools such as stereochemistry (Walden inversion), rate law analysis, and the effects of substrate, nucleophile, and leaving group variations on reaction rates. Study classic experiments by Kenyon and Phillips, as well as Bartlett and Knox, which established the nature of Walden inversion. Gain insights into kinetics and its role in studying mechanisms, and understand how substrate structure influences rate constants. This comprehensive lecture provides a solid foundation for understanding nucleophilic substitution tools and their applications in organic chemistry.